From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Test report on an Alfa-Romeo engine.
| Identifier | ExFiles\Box 179\2\ img225 | |
| Date | 10th February 1932 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Mths.{Reg Matthews} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} TEST REPORT OF ALFA-ROMEO ENGINE. ENGINE TYPE. This unit has bore of 65 m/m.{Mr Moon / Mr Moore} and stroke of 88 m/m.{Mr Moon / Mr Moore} giving a total capacity of 1750 cc's. The volume of each cylinder head is 63 cc's. giving a compression ratio of 5.35:1 when taking into account the displacement of Gasket, the pistons are level with top of cylinder block. A Rootes Type supercharger is driven from front of engine, the supercharger and mixture pipes are well supplied with cooling fins. Two blow-off valves are fitted to the mixture pipes but the pressure at which these valves blow off has not yet been determined. STARTING. The unit whilst on the bed was started by hand, xxx on all occasions, the self starter not being used because of its drain on the battery with no dynamo fitted. Starting from cold is very difficult and was accomplished by blanking up the air intake and flooding the carburetter several times. When warm the engine would start at the first pull up. For starting purposes the best sparking plugs were K.L.G. K.1 Type, these plugs were better than Champion R.3 Plugs as fitted when the engine was received and also better than Lodge A.40 Type as used for power curves etc. DISTRIBUTION. The distribution with the engine cold during warming up period was very poor, the front cylinders were very rich and No.2 cylinders cut-out on several occasions due to over-richness. When hot the distribution is fairly good over the whole speed range. CARBURETTER METERING. The Full Throttle Metering of the carburetter is fairly good above 1300 RPM. but below this speed the mixture is rather weak and the choke tube depression appears to be too low, the engine will not run at 500 RPM. owing to the depression being too low. The depression at the throttle is only .125" Mercury at 1000 RPM. The Throttled Metering when throttled from 3500 RPM. shows a weak spot at 1250 - 1300 RPM., this weak spot is very noticeable when accelerating, acceleration is very poor below 1250 RPM. | ||